Emergency call system with call capacity/last chance routing feature

A system for routing incoming emergency calls to answering points in one of a plurality of different calling areas, each said answering point having means for queuing said incoming emergency calls routed thereto, comprising:

• means for designating said incoming emergency calls from a given calling area to be routed to a selected one of said answering points;
• means for limiting the number of said incoming emergency calls that may be placed in said queuing means at each said answering point to a selectable call capacity limit number;
• and
• means for adding said incoming emergency calls from said given calling area to said queuing means of said selecting answering point only if the number of said incoming emergency calls in said queuing means has not reach said selectable call capacity limit number selected for said selected answering point.

A system for routing emergency calls to a selected answering point having a plurality of call answering workstations;

• said system having a notification line for said answering point and means for placing said emergency calls in a queue to said notification line;
• said answering point having means for handling said emergency calls routed to said workstations, comprising:
• means for limiting the number of said emergency calls that are simultaneously being handled by said answering point and in said queue, said limiting means setting a call capacity limit number;
• and
• means effective at a current time for adding to said queue another one of said emergency calls to be routed, said adding occurring only if the number of said emergency calls being handled by said answering point and in said queue has at said current time not reached said call capacity limit number.

A system for routing emergency calls to an answering point or to a second destination;

• said answering point having a notification line, means for placing in a queue said emergency calls to be routed to said notification line, and call answer terminals which may be active or inactive at a current time at which one of said emergency calls is to be routed, comprising:
• first means for determining the number of said terminals that are active at the current time;
• second means for setting a call capacity depth as a function of said number of active terminals at any current time;
• third means for multiplying said call capacity depth times said number of active terminals to obtain an answering point call capacity limit representing the maximum number of said emergency calls which may be in process of being handled by said answering point at any one of said current times;
• fourth means for determining the current number of said emergency calls which are in process of being handled by said answering point at said one current time;
• fifth means for determining whether said call capacity limit exceeds, equals or is less than said current number of said emergency calls;
• and
• sixth means for routing one of said emergency calls at said current time to said answering point if said fifth determining means determines that said call capacity limit exceeds said current number, and for routing said one call at said current time to said second destination if said call capacity limit is less than or equal to said current number of calls.

A system for routing emergency calls to a selected one of many destinations at which said emergency calls are to be answered, wherein there is at least one preferred type of destination and more than one destination of that type, wherein there is at least one second type of destination and more than one destination of that second type, comprising:

• first means for determining whether any of said destinations of said first type of destination is available at a current time to handle a given one of said emergency calls, said first determining means not necessarily making said determination as to all of the destinations of said preferred type such that at said current time there may be unchecked destinations of said preferred type;
• second means rendered effective upon said determining means not identifying any destination of said preferred type of destination as being available to handle said given emergency call for linearly searching said destinations of said first type to identify one or more of said unchecked destinations;
• for each said unchecked destination of said preferred type as may exist, third means effective for determining whether said unchecked destination is available to handle said given emergency call;
• said second means searching to identify another unchecked destination if said unchecked destination is not available to handle said given emergency call;
• and
• fourth means responsive to said second means not identifying any of said destinations of said preferred type as being available to handle said given emergency call for causing said second searching means to repeat said linear searching with respect to said destinations of said second type, said repeated linear searching determining whether there was any prior attempt made to route said given emergency call to any of said destination of said second type.

A system for routing emergency calls to one of many destinations at which the emergency calls are handled, wherein public safety answering points are a preferred type of destination, wherein switch directory numbers are a second type of destination and public switched telephone network directory numbers are a third type of destination, comprising:

• first means for determining whether there is any said public safety answering point to which no attempt was made to route a given one of said emergency calls, said first determining means not necessarily making said determination as to all of said public safety answering points such that there may be unattempted public safety answering points to which not attempt was made to route said given emergency call;
• second means rendered effective upon said first determining means not identifying one of said unattempted public safety answering points for sequentially searching all of said public safety answering points, said searching including all of said unattempted public safety answering points as may exist and determining whether any of said public safety answering points was unattempted;
• third means responsive to said searching means not identifying any of said public safety answering points as being unattempted for repeating said sequential searching with respect to said switch directory numbers, said repeated sequential search determining whether there is any said switch directory number to which no attempt was made to route said given emergency call;
• and
• fourth means responsive to said third means not identifying any of said switch directory numbers as being unattempted for repeating said sequential searching with respect to said public switched telephone network directory numbers, said last-mentioned repeated searching determining whether there is a public switched telephone network directory number to which no attempt was made to route said given emergency call.

In a system for routing an emergency call to one of many possible destinations;

• said possible destinations being in a preferred priority and including at least one public safety answering point, an alternate destination for said public safety answering point in the form of a routing switch directory number, or a third destination in the form of a public switching telephone network directory number;
• said system comprising means for routing said emergency call and means for sending commands to control said routing means;
• the improvement in said sending means comprising:
• last chance means for searching said destinations in a selected order in an attempt to identify one of said destinations that is available to handle said emergency call, said last chance means being effective after said routing means has failed to route said emergency call to one said destination that is first in said priority;
• first means responsive to said routing means failing to route said emergency call in response to one of said commands for determining if said routing means was attempting to route said emergency call to one of said public safety answering points;
• and
• second means effective whether or not said routing means was attempting to route said emergency call to one of said public safety answering points for determining if said last chance means was being used by said routing means to route said call.